The present invention relates to an oil cooler for cooling lubricant oil of an internal combustion engine. More specifically, the present invention pertains to an oil cooler that includes a cooling element having at least one channel with an inlet and outlet for a flowing coolant medium and that is disposed in a space containing lubricating oil.
Oil coolers for cooling lubricating oil are available in two main types. One type has the same basic design as a conventional cooler for engine coolant; that is, it is made up of a large number of thin strips of sheet metal joined together to form channels for oil and flow-through holes for an air flow such as from a coolant fan, which can be the same fan as is used for cooling the coolant in the coolant radiator. The other type has a container through which oil flows in the engine. The container contains a battery of tubes through which coolant flows thereby cooling the surrounding oil when it flows through the container.
Common to these two types of coolers is that they are arranged outside the engine block itself and are connected to the lubricant circuit via outer conduits. Firstly, this means that the engine oil pump must be dimensioned not only for the oil volume in the engine oil ducts, but also for an oil volume outside the engine. Secondly, these oil coolers, and the conduits thereto, must be dimensioned for the maximum oil pressure of the oil system. The advantage of the latter type compared to the former type is that the coolant is heated more rapidly than the oil, and for cold starts, the oil cooler first functions as a heating element for heating the oil before it needs to be cooled.
In view of the above described deficiencies associated with known solutions for cooling oil in internal combustion engines, the present invention has been developed to alleviate these drawbacks and provide further benefits to the user. These enhancements and benefits are described in greater detail hereinbelow with respect to exemplary embodiments of the present invention.
The present invention in its several disclosed embodiments alleviates the drawbacks described above with respect to oil coolers for internal combustion engines and incorporates several additional beneficial features.
The purpose of the present invention is to achieve a simple, effective and inexpensive oil cooler of the type described by way of introduction, that requires a minimum of conduit installation, and these conduits do not need to be dimensioned for the over-pressure of the oil circulating in the engine. This means that the oil pump only needs to be dimensioned for pumping oil to the engine itself and not to an oil cooler outside the engine.
This is achieved according to the invention by virtue of the fact that the cooling element is arranged in an engine sump, and that the inlet and the outlet have connections on the outside of the sump for connection to an engine cooling system.
In a preferred embodiment of the oil cooler according to the present invention, the cooling element includes an essentially rectangular, extruded and flat aluminum profile with coolant channels over at least the major portion of its extent. End pieces are fixed to a short sides of the aluminum profile and have channels that connect the coolant channels with each other and with inlet and outlet features. The aluminum profile is also made with an oil channel open at both ends, one end of which is disposed to be connected to an inlet tube which projects down into the oil sump, and the other end of which is disposed to be connected to a suction conduit of an oil pump.
An oil cooler of this type can be manufactured at lower cost than the previously known oil coolers described above. It has low weight and requires no installation of oil conduits outside the engine itself. When changing oil, all the oil is changed, in contrast to oil changing in an engine with one of the known oil coolers, where a certain amount of old oil will unavoidably remain in the oil coolers. An additional advantage of arranging an oil cooler in the sump is that it is completely protected from corrosion, something which is definitely not the case, for example, in an air-cooled cooling element placed next to the coolant cooler of the vehicle. At the same time, an important property of the previously known oil coolers is retained; that is, the oil cooler according to the present invention also functions as a heating element for heating the engine oil when cold-started.
The beneficial effects described above apply generally to the exemplary devices, mechanisms and methods disclosed herein for the present invention. The specific structures and steps through which these benefits are delivered will be described in greater detail hereinbelow.